Most vehicles with rear or front wheel drive have a differential. The differential balances the torque in the two axles. If an e motor is attached to the axle of the vehicle the e motor also needs to be connected with a differential. The differential is connected to the e motor output and axles of the drive train. The e motor provides torque input to the differential and the differential splits the torque into two axles. The e motor rotor may or may not be concentric, but the differential is used to split the e motor torque into two axles, each connected to a respective wheel.